Ignition device



April 4, H. sTADLER ETAL .mmm

IGNITION DEVICE Filed Sept. 8, 1964 INVENTOR1 HANS STADLER HEINZ GAWLICKSlate, L E,

Y A TTOR United States Patent C) M 3,312,168 IGNITIGN DEVICE HansStadler, Nurnherg, and Heinz Gawlick, Furth,

Bavaria, Germany, assignors to Dynamit Nobel Aktiengesellschaft,Troisdorf, Germany Filed Sept. 8, 1964, Ser. No. 395,616

Claims priority, appiication Germany, Sept. 7, 1963,

The present invention relates to an ignition device, and moreparticularly to a surface igniter for incendiary compositions.

Certain types of apparatus exist in which an incendiary composition hasto be ignited and more particularly in such a manner that the combustionor burning process sets in along the entire axial extent of theincendiary cornposition. For that purpose the incendiary composition isprovided with a recess, into which a so-called surfaceigniter isinserted which is called surface-igniter because it to ignite not onlywithin a narrow limited zone but over the entire surface thereof. Thesurface-igniters used heretofore consist in general of black powder andwere therefore sensitive against external influences and resulted inrelatively along ignition periods.

The surface-igniter according to the present invention assures acompletely satisfactory surface ignition by the following constructions:

A rapidly ignitable pyrotechnical mixture is assembled into a cartridgeabout a readily destructible hollow cylin der. A primer is installed atthe cartridge bottom whose ignition flash or jet pierces and crushes thehollow cylinder. The latter is destroyd thereby so that the ignitionflash or jet ignites the pyrotechnical mixture along the entire axialextent thereof. By reason of the very small ignition time that amountsonly to l millisecond or less, the incendiary composition is now ignitedimmediately over the entire axial extent thereof. In order to producewithin the hollow cylinder an ignition flash or jet which is as powerfulas possible, it is appropriate to provide a supplementary charge to therear of the primer, which produces the ignition llame or jet, properlyspeaking. During burning of the pyrotechnical mixture the cartridge casewhich consists of a readily destructble material is immediatelyeliminated so that the ignition llame can reach without obstruction theincendiary composition.

Paper and plastic material of any appropriate known type are thereby ofparticular consideration as materials for the hollow cylinder.

The pyrotechnical mixture is made `appropriately of about 75 parts ofbarium nitrate and of about 25 parts of magnesium powder or a powder ofan aluminum-magnesiurn alloy.

Accordingly, it is an object of the present invention to provide asurface-igniter of -the type described above which obviates thedrawbacks encountered with the prior art constructions.

It is another object of the present invention to provide a largesurface-ignition device that is essentially insensitive against externalinfluences and results in an ignition time that is extraordinarilyshort.

Another object of the present invention resides in the provision ofsurface-igniters for incendiary compositions or powder trains thatassure completely satisfactory ignition as well as reliable operation at.all times.

Still a further object of the present invention resides in the provision-of a surface-igniter that is capable of producing a powerful ignitioname without the detriments normally encountered therewith in the priorart.

These and other objects, features and advantages of the presentinvention will become more obvious from the 3,3 l2, l 68 Patented Apr.4, 1967 ICC following description when taken in connection with theaccompanying drawing which shows in the single figure thereof, forpurposes of illustration only, one embodiment in accordance with thepresent invention.

Referring now to the single figure of the drawing which is an axiallongitudinal cross section of one embodiment of a surface ignitiondevice of the present invention, the surface igniter illustrated thereinhas the shape of a cartridge and includes the bottom piece 5 made ofmetal and the case 6 consisting, for example, of plastic material andclosed at the top thereof. The lower zone 7 of the case 6 is reinforcedand provided with a recess into which, upon emplacement of the case 6over the neck portion of the bottom piece 5, snaps an annular collar 8.A cup 9 is secured at the bottom piece 5 and a cup 10 is worked into thetop of the case 6. A hollow cylinder 3 made of a readily destructiblematerial is inserted between the two cups 9 and 10. The pyrotechnicalmixture is designated in the drawing by reference numeral 4. As shown inthe drawing, the pyrotechnical mixture 4 surrounds the hollow cylinder3. Reference numeral 1 designates in the drawing -a primer ofconventional construction while reference numeral 2 designates a boostercharge also of any conventional composition.

Operation The operation of the surface-igniter according to the presentinvention is as follows:

During use of the surface-igniter according to the present invention,the primer 1 is ignited by any suitable known means which, in turn,ignites the booster charge 2. The separating or partition wall 11 formedby cup 9 and made of suitable material is thereby destroyed and theignition jet or flash enters into the hollow cylinder 3. Since thehollow cylinder 3 is, according to postulation, readily destructible, itis removed and eliminated by the gas pressure and/or the dame influence,and the ignition flash or jet can now ignite the pyrotechnical mixture 4instantaneously over its entire length. The case 6 is then destroyed`also and the ignition llame is brought into contact over the entirelength of the ignition charge 4 with the incendiary composition.

While we have shown and described one embodiment in accordance with thepresent invention, it is understood that the same is not limited theretobut is susceptible of numerous changes and modications as known to aperson skilled in the art, and we therefore do not wish to be limited tothe details shown and described herein but intend to cover all suchchanges and modifications as are encompassed by the scope of theappended claims.

We claim:

1. A surface igniter provided with ignition means for ignitingincendiary compositions, comprising a cartridge case having a tubularcase shaft closed at its forward end and a bottom piece closing therearward end of said tubular case shaft; a readily destructible axiallyextending hollow tubular body means within said cartridge case operableto form a substantially annular sealed chamber between said cartidgecase and said body means; an axially extending tiring channel formed byand within said body means consisting solely of gases, and extending forsubstantially the entire length of said tubular case shaft; a rapidlyignitible pyrotechnical mixture within said cartridge case substantiallyfilling said substantially annular sealed chamber; ignition meanslocated adjacent the rear of said body means for producing an ignitionflash .that will first enter and fill said tiring channel, and thenpierce and destroy said body means to ignite said pyrotechnical mixturesubstantially simultaneously over the entire internal surface adjacentsaid body means; said hollow tubular body means including a tubularmember and a separate cup-shaped member telescopically connected withthe rearward portion of said tubular member; said bottom piece having aforwardly extending projection; said cup-shaped member beingtelescopically connected with the forward portion of said projection;and said case shaft consisting of a readily destructible material.

2. A surface igniter according to claim 1, wherein said case shaftincludes a depending cup-shaped element at its forward closed endtelescopically connected with the forward end of said tubular member.

3. A surface igniter provided with ignition means for -ignitingincendiary compositions, comprising a cartridge case having a tubularcase shaft closed at its forward end and a bottom piece closing therearward end of said tubular -case shaft; a readily destructible axiallyextending hollow tubular body 4means within said cartridge case operableto form a substantially annular sealed chamber between said cartridgecase and said body means; an axially extending tiring channel formed byand within said body means consisting solely of gases, and extending forsubstantially the entire length of said tubular case shaft; a rapidlyignitible pyrotechnical mixture within said cartridge case substantiallyfilling said substantially annular sealed chamber; ignition meanslocated adjacent the rear of said body means for producing an ignitionflash that will first enter and till said firing channel, and thenpierce and destroy said body means to ignite said pyrotechnical mixturesubstantially simultaneously over the entire internal surface adjacentsaid body means; said hollow tubular body means including -a tubularmember; and a separate cup-shaped member telescopically connected withthe rearward portion of said tubular member and operatively connected tosaid bottom piece; said cup-shaped member including a transverselyextending partition wall means operable to close the rearward end ofsaid tubular member; said case shaft including a dependent cup-shapedelement at its forward closed end telescopically connected to theforward end of said tubular member; and said case shaft consisting of areadily destructible material.

4. A surface igniter provided Iwith ignition means for ignitingincendiary compositions, comprising a cartridge case having a tubularcase shaft closed at its forward end and a bottom piece closing therearward end of said tubulaicase shaft; a readily destructible axiallyextending hollow tubular body ymeans within said cartridge case operableto form a substantially annular sealed chamber between said cartridgecase and said body means; an axially extending firing channel formed byand within said body means consisting solely of gases, and extending forsubstantially the entire length of said tubular case shaft; a rapidly-ignitible pyrotechnical mixture within said cartridge casesubstantially lling said substantially annular sealed chamber; ignitionmeans located adjacent the rear of said body means for producing anignition flash that will first enter and fill said ring channel, andthen pierce and destroy said body means to ignite said pyrotechnicalmixture substantially simultaneously over the entire internal surfaceadjacent said body means; said hollow tubular body means including atubular member and ya separate cup-shaped member telescopicallyconnected with the rearward portion of said tubular member; said bottompiece having a forwardly extending projection; said cup-shaped memberbeing telescopically connected with the forward portion of saidprojection; said cup-shaped member including a transversely extendingpartition wall means operable to close the rearward end of said tubularmember and provide said cup-shaped member with substantially H-shapedcross-section; said bottom piece projection having an enlarged annularforward end; said cup-shaped member havin-g a rearward extending tubularportion engaging said projection annular enlargement and provided withan inwardly extending annular ange at its rearward end engaging therearward portion of said projection annular enlargement; said ignitionmeans including primer means and booster charge means partially locatedwithin said projection; said case shaft, including its forward endclosure, being homogeneously integrally made of plastic and including adepending homogeneously integrally plastic cup-shaped element at itsforward closed end telescopically connected with the forward end of saidtubular body means; and said case shaft consisting of a readilydestructible material,

References Cited by the Examiner UNITED STATES PATENTS 664,116 12/1900Barrallon 102-40 2,955,535 10/1960 Show et al. 102-70 X 2,959,00111/1960 Porter 60-356 FOREIGN PATENTS 215,863 6/1961 Austria.

1,706 12/1893 Great Britain.

BENJAMIN A. BORCHELT, Primary Examiner.

G. H. GLANZMAN, Assistant Examiner.

1. A SURFACE IGNITER PROVIDED WITH IGNITION MEANS FOR IGNITINGINCENDIARY COMPOSITIONS, COMPRISING A CARTRIDGE CASE HAVING A TUBULARCASE SHAFT CLOSED AT ITS FORWARD END AND A BOTTOM PIECE CLOSING THEREARWARD END OF SAID TUBULAR CASE SHAFT; A READILY DESTRUCTIBLE AXIALLYEXTENDING HOLLOW TUBULAR BODY MEANS WITHIN SAID CARTRIDGE CASE OPERABLETO FORM A SUBSTANTIALLY ANNULAR SEALED CHAMBER BETWEEN SAID CARTIDGECASE AND SAID BOIDY MEANS; AN AXIALLY EXTENDING FIRING CHANNEL FORMED BYAND WITHIN SAID BODY MEANS CONSISTING SOLELY OF GASES, AND EXTENDING FORSUBSTANTIALLY THE ENTIRE LENGTH OF SAID TUBULAR CASE SHAFT; A RAPIDLYIGNITIBLE PYROTECHNICAL MIXTURE WITHIN SAID CARTRIDGE CASE SUBSTANTIALLYFILLING SAID SUBSTANTIALLY ANNULAR SEALED CHAMBER; IGNITION MEANSLOCATED ADJACENT THE REAR OF SAID BODY MEANS FOR PRODUCING AN IGNITIONFLASH THAT WILL FIRST ENTER AND FILL SAID FIRING CHANNEL, AND THENPIERCE AND DESTROY SAID BODY MEANS TO IGNITE SAID PYROTECHNICAL MIXTURESUBSTANTIALLY SIMULTANEOUSLY OVER THE ENTIRE INTERNAL SURFACE ADJACENTSAID BODY MEANS; SAID HOLLOW TUBULAR BODY MEANS INCLUDING A TUBULARMEMBER AND A SEPARATE CUP-SHAPED MEMBER TELESCOPICALLY CONNECTED WITHTHE REARWARD PORTION OF SAID TUBULAR MEMBER; SAID BOTTOM PIECE HAVING AFORWARDLY EXTENDING PROJECTION; SAID CUP-SHAPED MEMBER BEINGTELESCOPICALLY CONNECTED WITH THE FORWARD PORTION OF SAID PROJECTION;AND SAID CASE SHAFT CONSISTING OF A READILY DESTRUCTIBLE MATERIAL.